Manufacture of brown sulfurized vat dyestuffs.



uuirnn STATES PATENT FFICE.

AUGUST LEOIOLD LASKA, 0F OFFENBACH-ON-THE-MAIN, GERMANY, ASSIGNOR TO THECORPORATION OF CHEMISCHE FABRIK GRIESHEIM ELEKTRON, OF FRANKFURT-ON-THE-MAIN, GERMANY.

MANUFACTURE OF BROWN SULFURIZED VAT DYESTUFFS.

No Drawing.

Specification of LettersPatent.

Application filed February 9, 1911. Serial No. 607,604.

Patented July 25, 1911.

To all whom it may concern:

Be it known that I, Auousr LEOPOLD LASKA, doctor of philosophy, chemist,a subjectof the German Emperor, and resident of Otfenbach-on-the-lvlain,in the Grand Duchy of Hesse, Germany, with post-office addressDreieichring No. 18, have invented new and useful Improvements in theManufacture of Brown Sulfurized'Vat Dyestuffs, of which the following isa specification.

In the specification of American Letters Patent Nr. 59798-3 blacksulfurized-dyestuffs have been described, obtained by heating withalkali polysulfids 1.5-dinitroanthraquinone or raw dinitroanthraquinone,obtained by nitrifying anthra'quinone, or products of reduction thereof.Now I have' found that quite difierent dyestuffs are obtained by heatingthe aforesaid anthraqui none derivatives with alkalipolysulfids(preferably under pressure), until a test portion of the products ofreaction no longer dissolves in aqueous solutions of alkali sulfids. Thethus obtained dyestuffs are insoluble in water, alkali-lyes, andsolutions of alkali sulfids. They bear the. properties of vat-dyestuffsand dye from the hydrosulfite-vat cotton very fast olive-brown shades. j

The following examples will serve to illustrate the nature of myinvention and in what manner the same can be carried out; parts being byweight.

Example I: 480 parts of crystallized sodium sulfid and 195 parts ofsulfur are dissolved in 700 parts of water. Into the solution areintroduced 150 parts of dinitroauthraquinone, whereupon the mixture isheated up to 200 C. in an autoclave during 12 hours. The melt is dilutedwith water and the precipitated part separated by straining, washed outwithwater and dried. The thus .obtaineddyestufi is a black powder,insoluble in alcohol, water, caustic soda lye and solutions of sodiumsulfid. By means of alkaline solutions of hydrosulfite a dark brown vatis obtained dyeing cotton very fast olive-brown shades.

. Example II: Into a solution of 7 50 parts of sodium sulfid and 250parts of sulfur in of reduction of dinitroanthraquinone) are introducedwhereupon the mixture is heated up to 230 C. during. 20 hours. The meltis diluted with water and the precipitated dyestuff separated byfiltering off and dried. It has essentially the same properties as thedyestuffs of Example I. I

Now what I claim and desire to secure by Letters Patent is thefollowing:

1. The process for manufacturing brown sulfurized vat dyestuffs,consisting in heating dinitroanthra'quinone, obtained by nitrifyinganthraquinone, with alkali polysulfids, until a test portion of theproducts of reaction no longer dissolves in aqueous solutions of alkalisulfids.

2. As new articles the sulfurized vat dyestuffs obtained by heating withalkali poly sulfids the dinitro-anthraquinone, obtained by dinitrifyinganthraquinone, until a test portion of the products of reaction nolonger dissolves in aqueous solutions of alkali sulfids; which dyestufisare black powders, insoluble in alcohol, water, caustic soda lye andsolutions of sodium sulfid, yielding by means of alkalinehydrosulfite-solutions a dark-brown vat, from which cotton is dyed veryfast olive-brown shades.

3. The process of manufacturing a brown sulfurized vat-dyestufi'consisting in heating 1.5-dinitroanthraquinone with alkali polysulfidsuntil the products of reaction no longer dissolve in aqueous solutionsof alkali sulfids.

4. As new articles the brown sulfurized vat dyestufl obtained by heating1.5-dinitroanthraquinone with alkalipolysulfids until the productsofreaction no longer dissolve in aqueous solutions of alkali sulfids;which dyestufi is a black powder, insoluble in a1eoas my invention, Ihave signed my name in 1101, Water, caustic soda lye, and solutions of vpresence of two Witnesses, this twenty-sixth sodium suifid yielding bymeans of alkaline 1 day of January 1911. hydroeuifite solution e darkbrown vet, I AUGUST LEOPOLD LASKA. from which cotton is dyed very fastoiivel Witnesses: brown shades. I HERMANN TEIL,

in testimony that I claim the foregoing 5 ROBERT BRIHL.

